Antiarrhythmic and hemodynamic responses to adenosine triphosphate during infusion of epinephrine in dogs anesthetized with halothane.

The effects of adenosine triphosphate (ATP) on cardiovascular responses to epinephrine were evaluated in dogs anesthetized with halothane. The dose of epinephrine required to induce arrhythmias averaged 1.05 +/- 0.52 microgram/kg/min. The dose of ATP required to abolish these arrhythmias averaged 1.64 +/- 0.67 mg/kg/min. ATP had not only an antiarrhythmic effect but also antagonized epinephrine-induced increases in heart rate, systemic vascular resistance, mean arterial blood pressure, and further increased cardiac index. ATP had, however, no significant effect on epinephrine-induced increases in myocardial contractility.